Hitachi GR2000 Series - Manual (Page 254)

Hitachi Gigabit Router GR2000 Series Enhanced Version Operations - Device Management Overview
7-88 GR2K-GA-0015
Ver. 07-02
Reception at exit edge router in non-VPN communication
In non-VPN communication, the label is omitted by the PHP from the LSR located
immediately before the exit edge router, allowing the packets to become ordinary
IPv4 packets.
Non-VPN communication through multipath route inside network
When the route inside the network consists of a multipath route, non-VPN
communication becomes the load balance of IPv4, and no MPLS communication
is enabled. In the VPN communication, labels are added, and the MPLS
communication is enabled.
Label display of traceroute command
When the traceroute command is executed on the LSR or remote site with which
MPLS communication is to be established from the unit, a label value will be
displayed if the responding router embeds it in its response. Since some
responding routers do not embed any label value in their response, it may
happen sometimes that no label value is displayed despite the fact that the
traceroute command is issued during the MPLS communication.
7.11.8 LDP session is not established
7.11.8.1 When the basic LDP session is not established
Firstly, check the state of the interface at the IP address specified in the LDP session
that was not established.
(a) When the interface is not in UP state:
Eliminate the interface fault in accordance with Section 7.4, Communication fault in
network interface.
(b) When the interface is in UP state:
Specify the detailed option with the show mpls ldp command to investigate the
reason the basic LDP session cannot be established. The table below shows fault
analysis methods to be followed when the basic LDP session is not established while
the interface is in UP state.
Table 7-37 Faulty analysis methods for basic LDP session
Item
No.
Confirmation contents and command Remedy
1 Check last down reason which is a result
indication of the show mpls ldp command Go to item (3) if the reason the basic LDP session last changed
from UP to Down is currently displayed.
"--" means that the basic LDP session was never established. In
that case, go to item (2).
2 Check the statistical information of the
hello message. If the reception count is 0, the hello message has not arrived from
the remote LSR. Check the state of the remote router and of the
link.
If the hello message has been received, check the state of the tcp
connection of the LDP session. Also check the state of the remote
LSR.